粉煤灰的矿物学特征与磁性矿物的分选

发布时间：2018-05-31 04:56

本文选题：粉煤灰 + 矿物学特征　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：我国作为煤炭大国,粉煤灰产量一直居高不下,2016年我国粉煤灰产量约达6亿吨,加上历年来堆存的,截止2016年底,粉煤灰积存量已达30亿吨。粉煤灰的应用领域虽然很多,但是应用量却十分有限。针对这一应用难题,对粉煤灰进行矿物学分析和磁性矿物分选试验,并对其中的矿物相含量进行测定,为粉煤灰的应用提供理论基础。研究结果表明:粉煤灰中各矿物相的平均粒径分别为玻璃体25.70μm,石英35.9μm,莫来石19.8μm,磁铁矿17.1μm,赤铁矿21.4μm,f-CaO 18.5μm。粉煤灰中玻璃体含量53.99%,石英含量25.53%,莫来石含量17.98%,磁铁矿含量1.72%,赤铁矿含量0.20%,f-CaO含量0.15%;粉煤灰中磁铁矿的单体解离度为28.73%,赤铁矿的单体解离度为15.48%,玻璃体的单体解离度为57.65%,其中粉煤灰中的玻璃体多以单体或与其他矿物呈两相连生关系存在;粉煤灰的颗粒密度分布范围主要集中在2.6~3.2g/cm3。粉煤灰中各种矿物相在碱、酸溶液中的溶解反应特征,采用碱-酸(NaOH-HNO3)两段溶解来测定粉煤灰中玻璃体含量的化学物相分析法。粉煤灰中莫来石、石英、磁铁矿、赤铁矿和未燃尽碳粒,在碱、酸溶液中是稳定相;玻璃体和f-CaO在碱溶液中反应形成凝胶,凝胶在酸溶液中完全溶解,表现为溶解过程的质量缩减率,减去f-CaO含量即为玻璃体含量。采用Rietveld全谱拟合法测定粉煤灰中磁性矿物的含量。测得粉煤灰原料中磁性矿物含量为2.05%;将粉煤灰分成不同粒级后,磁性矿物含量随粒级的增大而增多,+106μm粒级中磁性矿物含量为6.42%,是-30μm粒级的11.46倍,是原料的3.13倍,由各粒级中磁性矿物的富集系数知,粉煤灰中磁性矿物主要在粗粒级中富集,随着粒级的增大,富集系数也增大。粉煤灰由O-Sepa选粉机,气力分选得粗粉和细粉两种产品。文中选用3种风量进行气力分选,分别为Q1、Q2和Q3。得到三种中位分离径分别为22μm、30μm和35μm,应用牛顿分离效率对气力分选效果进行表征。Q1的牛顿分离效率为75.46%,Q2为80.35%,Q3为85.8%,三种风量下,Q3的分选效果较好。当进风量为Q3下,粗粉中磁性矿物含量为3.07%,玻璃体含量58.83%,细粉中磁性矿物含量较少为0.23%,玻璃体含量57.22%,气力分选产品粗粉中磁性矿物含量是细粉的13.35倍,粉煤灰经气力分选后,磁性矿物在粗粉中富集。
[Abstract]:As a big country of coal, the production of fly ash in China has been high all the time. In 2016, the output of fly ash in China has reached about 600 million tons, plus the accumulated amount of fly ash has reached 3 billion tons by the end of 2016. Although the application field of fly ash is many, but the application quantity is very limited. In view of this problem, the mineralogical analysis and magnetic mineral separation test of fly ash are carried out, and the content of mineral phase is determined, which provides a theoretical basis for the application of fly ash. The results show that the average particle sizes of each mineral phase in fly ash are vitreous 25.70 渭 m, quartz 35.9 渭 m, mullite 19.8 渭 m, magnetite 17.1 渭 m, hematite 21.4 渭 m, f-CaO 18.5 渭 m. The vitreous content in fly ash is 53.99, quartz 25.53, mullite 17.98, magnetite 1.72, hematite 0.20 and f-CaO 0.15.The monomer dissociation degree of magnetite in fly ash is 28.73, the monomer dissociation degree of hematite is 15.48, the monomer dissociation of vitreous is 15.48. The degree of vitreous in fly ash is 57.65. The vitreous body in fly ash exists in two contiguous relationship with other minerals. The particle density distribution of fly ash is mainly in the range of 2.6 ~ 3.2g / cm ~ (-3). The characteristics of dissolution reaction of various mineral phases in fly ash in alkali and acid solution. The chemical phase analysis method for the determination of vitreous content in fly ash by alkali-acid NaOH-HNO _ 3 two-stage dissolution is described. In fly ash, mullite, quartz, magnetite, hematite and unburned carbon particles are stable phases in alkali and acid solutions. Vitreous and f-CaO react in alkali solutions to form gels, which are completely dissolved in acid solutions. The content of vitreous is reduced by subtracting the content of f-CaO. The content of magnetic minerals in fly ash was determined by Rietveld full spectrum fitting method. The content of magnetic minerals in the raw material of fly ash is 2.05. The content of magnetic minerals in 106 渭 m particles is 6.42, 11.46 times that of -30 渭 m and 3.13 times of that of raw materials. According to the enrichment coefficient of magnetic minerals in each grain grade, the magnetic minerals in fly ash are mainly enriched in coarse grained grade, and the enrichment coefficient increases with the increase of particle size. Fly ash by O-Sepa separator, pneumatic separation of coarse powder and fine powder two products. In this paper, three kinds of air volume are selected for pneumatic separation, which are Q1, Q2 and Q3, respectively. The three median separation diameters were 22 渭 m 30 渭 m and 35 渭 m, respectively. The Newtonian separation efficiency of Q1 was 75.46 and 80.35, respectively. When the air volume is Q3, the content of magnetic minerals in coarse powder is 3.07, the content of vitreous is 58.83, the content of magnetic mineral in fine powder is less 0.23 and the content of vitreous is 57.22. The content of magnetic mineral in coarse powder of pneumatic separation product is 13.35 times that of fine powder. Magnetic minerals are enriched in coarse powder.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ536.4;TD91

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